well you see the population bit
self-discard often involves lots of rummaging and looting to filter through your deck, giving you plenty of time to find the perfect answer and keep the game going until you dig towards you win conditions
Release date: 2015-08-20 Akroma, Angel of Fury Akroma, Angel of Wrath Archangel of Strife Aurelia, the Warleader Avacyn, Angel of Hope Baneslayer Angel Entreat the Angels Exalted Angel Iona, Shield of Emeria Iridescent Angel Jenara, Asura of War Lightning Angel Platinum Angel Serra Angel Tariel, Reckoner of Souls
We already have a couple of enchantment decks built around cards like Hallowed Haunting that could easily run Invasion of Theros to tutor Heliod, the Radiant Dawn and Ossification and then flip into Ephara, which seems like a tough card to beat outside of a Farewell or Sunfall
Stony Silence Hates on Affinity but a little less harder than Kataki, while proving much more effective against Tron
They didnt want tough characters like Mufasa to be stuck in the Silver ink color and allow players building decks to have access to multiple versions of the same character